Various motion control and support devices are known in art to control and support tilt and/or rotational motion. Common prior art examples are found in chairs, such as office chairs that offer a variety of options for adjusting the tilt on a chair or restricting the degree to which a user of the chair is able to adjust and/or control the motion of the chair. A common example are office chairs that have various degrees of freedom and ranges of motion aimed at providing mobility, flexibility and optimal ergonomic positioning with minimal dynamic action. On problem associated with such prior art ergonomic designs is that they allow for an individual fit, but rarely are they readjusted as often as they should, so a user ends up sitting in a fixed position for prolonged periods of time when seated at an office desk. For example, these chairs are able to swivel, flexibly tilt in limited fore and aft plans and be raised and lowered as required by a user. Various mechanisms have been proposed or otherwise known in the art to provide some of the above-mentioned features. There are conventional adjustable chairs where adjustment is possible by way of several, independent adjusting means, to adjust, for example, chair height, angle, etc. In addition, active adjustment chairs provide for multi-directional adjustment based on the seating position of a user. Some problems associated with prior art systems include the complexity of the mechanisms involved, difficulty in operation, lack of fluid control over the motion of the tilt and/or rotation of the chair.
Furthermore, other resistive support devices have been used where control and dampening of the motion available is more important, or where temporary motion may be desirable. These include, for example, construction worker supports, mining support devices, and exercise equipment. In the exercise equipment example, prior art support devices aim to provide a resistance against movement of a user, while the user is either trying to maintain a constant position or is otherwise partaking in an exercise activity. Resistive support devices in this example are generally targeted at improving the core strength of a user.
The various prior art devices are generally restricted in the range of motion they support, and in the resistive forces that are applied. That is, resistive support is provided for only a small range of motion. Furthermore, prior art devices and mechanisms for providing such resistive support are generally not readily adaptable to different applications, and do not provide variable resistance throughout the range of motion. Furthermore, in the case of resistive support devices provided on chairs, such resistive support devices have heretofore been inadequate in providing core support and strengthening to a user on the chair, and have not provided a full range of resistive support throughout a full range of tilt and rotational motions. Some shortcomings of these prior art designs include a requirement that a pivot point for motion be at a distance significantly below the user's centre of mass, thereby requiring the user to lean their body more than to mobilize their pelvic and lower back skeletal structure minimizing their significant to the action of an active sitting surface. Some examples of such prior art devices include those shown in U.S. Pat. No. 7,547,067 to Keilhauer and U.S. Pat. No. 6,997,511 to Marchand.
One such example of a prior art chair having a resistive support mechanism is shown in U.S. Pat. No. 6,209,958 issued Apr. 3, 2001 to Thole et al. Thole discloses one way of implementing a tilt control mechanism on a seating assembly. However, the Thole mechanism, while providing for universal tilt, does not allow for a full range of positions in which the chair can be locked, or for full flexibility in the degree of resistance. Thole discloses a tilt control mechanism for a char, where the tilt control mechanism defines a pivot connection between a seat assembly and a base, whereby the seat assembly effectively pivots about a pivot point in any direction extending radially from the pivot point. The tilt control mechanism includes an annular elastomeric ring which resists multi-directional tilting by mimicking a spring effect in the resistance, and further biases the seat assembly to a neutral position. The elastomeric ring has a contact area on which the tilting moment of the seat assembly acts which contact area can be selectively varied to adjust tilting resistance. Accordingly, the Thole mechanism tends to be large and bulky where a wide range of resistances is required. Furthermore, there is no discussion in Thole or features provided that result in proper support for the core muscles in a user's body. There is therefore a need in the art for a tilt mechanism for a chair, or other support surface, that addresses at least one of the deficiencies of Thole.
It is therefore an object of the invention to provide a novel resistive support mechanism for use with surfaces designed to support a user, such as chairs.